Several biochemical processes are known, such as for example extraction and purification of nucleic acids (DNA, RNA), viral enrichment, subparticle enrichment or sedimentation and purification of proteins, which are performed by means of a sequence of one or more steps, among which the following are mentioned merely by way of example: mixing of a sample with one or more agents, lysis of biological material, sedimentation, separation by centrifugation, removal of waste fractions of the process, washing with suitable agents, and others.
These processes are performed within reactors or test tubes which are typically constituted by a cylindrical vessel which is closed at the bottom and provided with an upper opening with which a closure stopper is detachably associated.
To perform the different steps, in particular the steps which provide for the addition of process agents (lysis agents, washing agents, or others) or the removal of waste fractions, it is necessary to remove the closure stopper and then reapply it.
Moreover, if these addition or removal steps are separated by centrifugation steps, it is also necessary to remove the reactors from the centrifugation device.
These known reactors suffer drawbacks, among which mention is made of the fact that they require the execution of successive handling, opening and closure operations, which in addition to being awkward entail an onerous expenditure of time and costs.
Another drawback of known reactors consists in that particularly if the biochemical processes are performed manually, they entail high safety risks for the assigned personnel. Considering the fact that the processed biological material often contains infectious or pathogenic agents, the successive operations for handling, opening and closing known reactors in fact entail risks of infection of assigned personnel or of sample contamination, a phenomenon known as “carry over”.
Another disadvantage consists in that the automation of the biochemical processes performed in reactors of the known type requires the use of tools, such as handling robots, which are structurally and constructively complicated, require the assistance of complex and expensive management and control apparatuses, and require frequent maintenance.
With particular reference to the extraction and purification of nucleic acids (DNA-RNA), different processes are known which can be divided into processes based on the use of so-called “magnetic beads” and processes based on the use of filters.
In processes based on the use of magnetic beads, separation of the nucleic acids from the sample is achieved by using magnetic particles made of iron and coated with silica. These particles are dispersed in a reactor which contains an aqueous solution of nucleic acid. The nucleic acid adheres to the outer surface of the particles, forming hydrogen bonds. A magnetic field is then applied to the outside of the container so as to convey the particles, with the nucleic acid adhered thereto, to a preset region of such reactor, so as to allow removal of the aqueous solution and execution of the necessary washes without losing the particles with the nucleic acid adhered thereto. The nucleic acid thus separated is then eluted.
In processes based on the use of filters, separation of the nucleic acids from the sample is achieved by using silica particles to which the nucleic acid adheres with hydrogen bonds.
Both of these known processes for extracting nucleic acids suffer drawbacks, among which mention must be made of the fact that they allow to process limited volumes of samples, i.e., no more than 0.3-0.5 ml; they in fact provide for the use of commercial containers, generally plates with 48/96 wells, in which the volume per well is generally less than 2 ml.
Another drawback of these known extraction processes consists in that they do not ensure extraction of all the nucleic acid that is present in the sample due to the weakness of the hydrogen bond with which the nucleic acid adheres to the silica particles, be they magnetic or not.
Moreover, these known extraction processes are performed in known types of reactors and therefore suffer all the already-mentioned drawbacks linked to the use of such reactors.